Jenkins was among a group of players to work out for the Cowboys last week that included running backs Ben Tate, Felix Jones, Daniel Thomas and wide receiver Kris Durham.
Jenkins was the 30th overall pick by the San Francisco 49ers in 2012, but did not catch a pass in three games. He was traded to the Kansas City Chiefs in 2013, and caught 17 passes for 223 yards in 2013 and '14.
The Cowboys opened their first of nine organized team activities Tuesday.
With Dez Bryant not expected to take part in any of the remaining offseason program, the Cowboys wanted to add another veteran at receiver. Terrance Williams and Devin Street have worked with the first group in Bryant's absence, with Cole Beasley taking up his slot role.
The Cowboys did not select a receiver in this year's draft, but added George Farmer, with $55,000 in guaranteed money, Antwan Goodley and Lucky Whitehead as undrafted free agents. Executive vice president Stephen Jones said the undrafted trio was the best group the Cowboys have had at receiver since they signed Miles Austin and Sam Hurd in 2006.
To make room for Jenkins, the Cowboys waived/injured wide receiver Chris Boyd.